CeCILL is a French free software license designed to comply with French law while being compatible with the GNU General Public License (GPL). It aims to facilitate the distribution of free software in a legally sound manner, addressing specific legal frameworks within France and the European Union. The CeCILL license is part of a family of licences and is often used by French developers and organizations to ensure that their software can be freely used, modified, and distributed, while providing legal protections similar to those offered by the GPL.